Skip to main content
. 2001 Nov 6;98(24):13631–13636. doi: 10.1073/pnas.231071698

Figure 4.

Figure 4

Ser-388 is required for UBF activity in vivo and in vitro. (A) UBF1/S388G does not activate rDNA transcription in vivo. NIH 3T3 cells were transfected with 10 μg of pMr1930-BH together with 1 and 2.5 μg of pRc/CMV-FLAG-UBF1 (lanes 2 and 3), pRc/CMV-FLAG-UBF1/S388G (lanes 4 and 5), and pRc/CMV-FLAG-UBF1/S388D (lanes 6 and 7). Transcripts from the reporter plasmid were analyzed on Northern blots by using a plasmid-specific riboprobe. The blot was rehybridized with a riboprobe against cytochrome c oxidase (cox 1). To monitor FLAG-UBF1 expression, 10 μg of protein from the transfected cells were subjected to Western blotting by using antibodies against the FLAG epitope (M2). (B) Replacement of Ser-388 by aspartate does not impair UBF1 function. FLAG-tagged UBF1, UBF1/S388G, and UBF1/S388D were immunopurified from NIH 3T3 cells and assayed in a reconstituted transcription system.